Hi There--although you can make this sweater with *any* yarn, several of you have asked where to find the Be Sweet yarn pictured in two of the photos. It is very cool yarn, and it has a cool story. Nadine Curtis who owns the company works with a cooperative of women in South Africa who dye and spin the mohair. They also make finished items to sell. Money from the yarn goes to support local schools in South Africa, and the women of the cooperative are creating a sustainable business for themselves.
The yarn itself is light-weight, while being very warm. It is less itchy than many mohairs I've worked with, and it goes a long way--I got my own sweater out of 3 balls of yarn!
The Be Sweet web site lists stores that sell the yarn, and many of them have web sites, so i'm sure you can order it online.